Anyone who has ever had a bad break-up will know the cathartic pleasure of having a good old cry to an emotional song. (Just ask Adele.)

But what is it exactly about music that triggers an emotional response in us? What constitutes 'happy' or 'sad' music, or, more specifically, what makes us deem a certain song perfect for, say, a road trip rather than a meditation session?

"The emotional response people have to music is basically predicted by two main factors," Professor Adrian North, Head of School of Psychology and Speech Pathology at Curtin University, told The Huffington Post Australia.

"The first is whether it's considered to be pleasant or unpleasant, and the second is how 'active' versus 'sleepy' the music is."

Getty

"So, 'exciting' music might be something that we deem to be pleasant and active, while 'relaxing' music is something we perceive to be pleasant and sleepy.

"We might think a piece of music is boring if it's sleepy and unpleasant, or unsettling if it's active or unpleasant."

According to North, this system of measuring our response to music only really works if we are listening to a piece of music for the first time.

"That is based to on people's snap reaction to a piece of music they have never heard before," North said. "Beyond that, there are other things you have to take into consideration.

"Personal experience is one. If, for instance, a 'relaxing' song was playing on the car radio at the moment you hurtled over a cliff, for the rest of your life that piece of music is likely to be unsettling for you.

"Or you can take a more meta approach and ask, 'why do we like music that is sad?' It makes no sense," he continued. "Now there are various explanations to this, one of which is we feel good about feeling sad and that's what we are getting from the music."

AF archive / Alamy
Bridget Jones knows a thing or two about a good emotional power ballad.

Where North says things get particularly interesting is when you consider how advancements in technology have impacted on the way music impacts our everyday life.

"We can carry our entire music library -- in fact, all recorded music, ever -- by subscribing to a streaming service," North said. "As such, you can argue music is becoming increasingly immersed in everyday life. It's not just due to the technology that's arrived on the scene, either. It's also because we now have this understanding in how music is going to map onto our everyday life."

In terms of that last statement, North refers to the increasing popularity of playlists, which are often grouped into sub-categories such as 'work out', 'sleep' or 'party'. In other words, North says we are now able to categorise a particular piece of music in a way that is specific to a certain activity, all based on how that piece of music makes us feel.

"All these playlists recommended to you [by streaming services] bank around that theory of pleasantness and activity," North said. "[The consumer] is usually not aware of the fact they are doing that, but it's not a coincidence.

"We're seeing an increase in people using music for particular activities. For instance, at around 5-6 pm, there tends to be a spike in calming music, and that's because people want to unwind after a day at work."

Matt Sayles/Invision/AP
Adele: indisputable Queen of the tearjerker.

Powerful though the link between music and emotion may be, North says it's not so strong you can use it as a way to change your mood. In other words, blasting 'MmmBop' at a grumpy person will not cheer them up.

"If someone is in a grumpy mood and is determined to be in a grumpy mood, simply playing them a happy song is not going to shift that," North said.

In fact, North says one of the most powerful things about music -- and a major reason for its enduring popularity -- is that it can essentially be ignored.

"People to tend to have music on in the background," he said. "It's not as though, if you had a dinner party with friends, you could leave the TV on in the background. TV is also a visual medium. It requires both your eyes and ears, and your constant attention.

"With music, you can tune in and out. That fact it's not all consuming is actually a massive advantage in terms of where music stands on the media landscape."

"Can you imagine going to play and only paying attention to one minute out of three?" North continued. "It's only music you can do that with.

"And its influence is gaining. If you look at the dramatic increases to subscription rates, clearly people are finding a use for all this stuff.

"I find it incredibly exciting because at the moment, in 2016, we are seeing a perfect marriage between the theoretical understanding of how music works and the technology that allows us to use it pretty much whenever we want.

"As a result, of course we are seeing that it impacts people in their everyday lives, more so than ever before.

"As a species, if you like, we feel like music helps us. That's the only way you can explain it persisting for so long​."

To find out more about Professor North's current research project, head here.